“I think he would be terribly unfit for office. I don’t think he has the temperament to be president,” Romney said.

Romney, the GOP presidential nominee in 2012, gave a fairly unprecedented speech the day before in which he ripped Trump as a “phony,” “fraud,” “con man,” and “fake.” But Trump has been more than willing to return fire.

During his Friday speech in Michigan, Trump suggested that Romney’s speech was motivated by jealousy. Trump said Romney disliked him because he told the “choke artist” not to run for president again in 2016.

“This guy Romney came out yesterday. I mean, the hatred he has — the hatred, the jealousy, the hatred — it’s hard to believe,” Trump said.

Trump criticised Romney for not campaigning aggressively enough, for not performing well in the final two general-election debates against President Barack Obama, and for his infamous “47%” gaffe, in which Romney was caught on tape dismissing nearly half the country supposedly dependent on government benefits.

“In one speech he lost 47% of the voters. Can you believe it? He’s not a smart guy. This is not a smart guy,” he said of Romney.

Trump stressed that he had strongly supported Romney’s campaign in 2012:

You know the sad part is I really helped the guy. I mean, I gave him a lot of money. I raised a lot of money. I had two fundraisers in my apartment. In fact, one of them was such a rainy day that it ruined the carpets of my apartment. Everyone’s coming in, I had hundreds of people. My carpets were ruined. I think I’m going to send him a bill for new carpets. But here’s a disloyal guy.

Trump went on to brag that his net worth was far greater than Romney’s:

He’s an elitist. You see, to me I don’t consider him elite. But hey, I don’t consider him elite because I’m much richer than he is. I have a store — I have a store — that’s worth more money than him. I jokingly said that because I don’t like Romney.

He later compared Romney’s two failed presidential bids to an NFL kicker who missed a late-game kick.

“When you miss the kick one year, you miss the kick the next year,” Trump told his supporters. “Once a choker, always a choker.”

Romney was clearly on Trump’s mind throughout his speech. While explaining that his trade policies would be “really, really, really smart trade” instead of ideologically pure “free trade,” Trump went back to criticising Romney.